Digital lighting technologies, i.e. illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. LEDs offer many advantages, including controllability, high energy conversion and optical efficiency, durability, and lower operating costs. Recent advances in controllable LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications.
Alongside the development of controllable LEDs, rapid developments have been made in the area of sensor technologies. Sensors todays are not only able to effectively measure natural illumination and occupancy, but have also become significantly smaller, and therefore able to easily fit inside small devices, including devices housing controllable LEDs and cameras. For example, existing natural illumination based lighting control systems are able to employ individually controllable luminaires with dimming ballasts as well as one or more natural illumination photo sensors to measure the average workplane illumination within a naturally illuminated space. In such systems, one or more controllers, in order to respond to daylight egress and maintain a minimum workplane illumination, may monitor the output of one or more photosensors and control illumination provided by the luminaires.
More recently, innovations in the realms of wireless communication and smart mobile devices have launched a generation of smart phones and tablet computers with unparalleled mobility and computational power. For example, mobile smart phones with access to applications on cloud servers are able to gather, and process data from their immediate environments in real time. Additionally, location-based services allow for the customization of information delivered to mobile devices. Smart mobile devices, used in conjunction with controllable LEDs and appropriate sensors can therefore be used to customize illumination in physical spaces in real time.
Two further significant technological developments present further opportunities for innovations in the area of environmental management and control: Power over Ethernet (PoE) and Coded Light (CL). PoE allows for the delivery of electrical power along with data over a single cable to devices such as lighting devices, IP cameras or wireless access points. The advent of PoE technology makes it feasible to power devices in remote locations within building structures, by significantly reducing the need for electricians to install conduit, electrical wiring, and outlets. Unlike other devices, the potential location of a PoE device is not limited based on the placement of AC outlets within a structure. For example, PoE allows wireless LAN access points to be placed on ceilings for more optimal RF reception.
CL technology can be used to embed unique identifiers, or codes, into the light output from different light sources. Using these identifiers, the light emanating from a specific light source can be differentiated even in the presence of illumination contributions from multiple other light sources. CL can therefore be used to identify and locate individual light sources and devices relative to other such sources and devices. The use of light as a means for device identification, location and communication opens the door to innovative systems and methods for managing environmental conditions by allowing fine-grained interactions between devices such as individually controllable LEDs, sensors, and control devices such as smart phones that were not previously feasible.
These technologies may be combined in an ‘intelligent luminaire’. In other words an intelligent luminaire may be a luminaire that consists of a lighting unit, one or more (connections to) sensors and a microcontroller which is executing some logic/intelligent behavior, and has some communications means to interface with an area controller or directly with one or more neighboring luminaires.
As these luminaires become more and more complex, the control logic (formed from a combination of hardware and software elements) needed to control these luminaires also becomes increasingly complex. Furthermore a lighting system comprising the intelligent luminaires may further comprise sensors which also have microcontrollers on board (for example occupancy sensors which may be equipped with algorithms and software to accurately determine occupancy of a room or space). This may lead to situations where partial failures may be difficult to detect or diagnose.
Furthermore the distributed nature of such lighting systems (comprising intelligent luminaires and intelligent sensors) may further leads to difficulty in analyzing and diagnosing problems, or even detecting faults or failures within the system. For example because of the nature of most modern systems a single defective sensor in an open office consisting of many intelligent luminaires with each having a sensor, may not be easily detected provided there is sufficient occupancy in the open office. (In other words as long as one of the sensors is triggered, it should result in occupancy for the entire room being determined and the lights controlled to be on)